Heat spreader interconnect for thermally enhanced PBGA packages

ABSTRACT

A new method is provided for the interface between a heat spreader and the substrate of a thermally improved PBGA package. The heat spreader interfaces with the substrate with the standoff of the heat spreader. The stand-off of the heat spreader is provided with an opening, the stand-off of the heat spreader is aligned with the substrate of the PBGA package by means of a copper pad that is provided over a second surface of the substrate. A gold stud bump or a solder bump are further provided over the surface of the copper pad for alignment purposes. Thermally conductive epoxy or solder is deposited over the opening of the heat spreader and therewith over the copper pad provided over a second surface of the substrate. Under an additional embodiment of the invention, extremities if the heat spreader stand-off are aligned with contact pads provided over the second surface of the substrate of the package, thermally conductive epoxy is deposited over the contact surfaces between the extremities and the contact pads.

BACKGROUND OF THE INVENTION

[0001] (1) Field of the Invention

[0002] The invention relates to the fabrication of integrated circuitdevices, and more particularly, to a method and package for thermallyimproved Plastic Ball Grid Array (PBGA) packaging.

[0003] (2) Description of the Prior Art

[0004] The semiconductor industry has since its inception achievedimprovements in the performance of semiconductor devices by deviceminiaturization and by increasing the device packaging

[0005] One of the original approaches that has been used to createsurface mounted, high pin count integrated circuit packages has been theuse of the QuadFlat Pack (QFP) with various pin configurations. For theQFP, closely spaced leads along the four edges of the flat package areused for making electrical connections from where the electricalconnections are distributed to the surrounding circuitry. Theinput/output (I/O) connections that can be made to the QFP are thereforeconfined to the edges of the flat package, which limits the number ofI/O connections that can be made to the QFP even in applications wherethe pin to pin spacing is small. The QFP has found to be cost effectivefor semiconductor devices where the device 10 pin count does not exceed200. To circumvent this limitation, a new package, a Ball Grid Array(BGA) package has been introduced. For the BGA package, the electricalcontact points are distributed over the entire bottom surface of thepackage thereby eliminating the restriction of having I/O connects onlyaround the periphery of the package. More contact points with greaterspacing between the contact points can therefore be allocated across theBGA package than was the case with the QFP. The contact points that areused for the BGA package are typically solder balls that have the addedadvantage of facilitating flow soldering of the package onto a printedcircuit board.

[0006] Prior Art substrate packaging uses ceramic and plastic BGApackaging. Ceramic substrate packaging is expensive and has proven tolimit the performance of the overall package. Recent years have seen theemergence of plastic BGA packaging; this packaging has become the mainstream design and is frequently used in high volume BGA packagefabrication. The Plastic substrate BGA (PBGA) package performssatisfactorily when used for low-density flip-chip IC's. If the numberof pins emanating from the IC is high, that is in excess of 350 pins, orif the number of pins coming from the IC is less than 350 but therequired overall package size is small, or if the chip power dissipationis high (in excess of 4 Watts per chip), the plastic structure becomescomplicated and expensive.

[0007] The invention addresses concerns of thermal performance of thePBGA package that in addition provides advantages of electricalperformance (such as low parasitic inductance being added by thepackage) and advantages of assembly (such as low cost, being a flexiblesolution that does not require a redesign of the substrate over whichthe die is mounted) while the package meets conventional manufacturingstandards.

[0008] U.S. Pat. No. 5,372,396 (Fujimoto) shows a heat spreader using amold compound and a mold cavity.

[0009] U.S. Pat. No. 5,641,987 (Lee) shows another similar heat spreaderdesign.

[0010] U.S. Pat. Nos. 5,977,626 (Want et al.) 6,201,301 (Hoang) and5,834,839 (Mertol) show related heat spreaders and methods.

[0011] A principle objective of the invention is to provide asemiconductor package of improved thermal and electrical conductivity byusing conductive epoxy combined with solder ball interconnects toconnect between a heat spreader and a ground pad of the packagesubstrate.

[0012] Another objective of the invention is to provide a semiconductorpackage with improved heat spreader planarity.

[0013] Yet another objective of the invention is to provide asemiconductor package having direct contact between a heat spreader ofthe package and a substrate of the package.

[0014] In accordance with the objectives of the invention a new methodis provided for the interface between a heat spreader and the substrateof a thermally improved PBGA package. The heat spreader interfaces withthe substrate with the stand-off of the heat spreader. Under a firstembodiment of the invention, the stand-off of the heat spreader isprovided with an opening, the stand-off of the heat spreader andtherewith the heat spreader is aligned with the substrate of the PBGApackage by means of a copper pad that is provided over a second surfaceof the substrate. Thermally conductive epoxy is deposited over theopening of the heat spreader and therewith over the copper pad providedover a second surface of the substrate.

[0015] Under a second embodiment of the invention, the stand-off of theheat spreader is provided with an opening, the stand-off of the heatspreader and therewith the heat spreader is aligned with the substrateof the PBGA package by means of a gold bump or stud that is providedover a second surface of the substrate. Thermally conductive epoxy isdeposited over the opening of the heat spreader and therewith over thegold bump or stud provided over a second surface of the substrate.

[0016] Under a third embodiment of the invention, the stand-off of theheat spreader is provided with an opening, the stand-off of the heatspreader and therewith the heat spreader is aligned with the substrateof the PBGA package by means of a ground pad over which a solder ball isprovided over a second surface of the substrate. Thermally conductiveepoxy is deposited over the opening of the heat spreader and therewithover the ground pad and the thereover created solder ball provided overa second surface of the substrate.

[0017] Under a fourth embodiment of the invention, the standoff of theheat spreader and therewith the heat spreader is aligned with a copperground pad provided over a second surface of the substrate. Thermallyconductive epoxy is deposited over an extremity of the standoff of theheat spreader and therewith over the exposed surface of the copper padprovided over a second surface of the substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018]FIG. 1 shows a cross section of a conventional thermally enhancedPBGA package, specifically highlighting conventional methods of heatspreader interconnect.

[0019]FIGS. 2a and 2 b show a cross section of a first PBGA package ofthe invention, whereby the heat spreader is aligned by means of a copperpad provided over a second surface of the substrate.

[0020]FIGS. 3a and 3 b show a cross section of a second PBGA package ofthe invention, whereby the heat spreader is aligned with the underlyingsubstrate of the package by means of a gold stud or bump that is createdover a copper ground pad provided in the second surface of the substrateof the package.

[0021]FIGS. 4a and 4 b show a cross section of a third PBGA package ofthe invention whereby the heat spreader is aligned with the underlyingsubstrate of the package by means of a solder ball that is created overa copper ground pad provided in the second surface of the substrate ofthe package.

[0022]FIGS. 5a and 5 b show a cross section of a fourth PBGA package ofthe invention, whereby the stand-off of the heat spreader is alignedwith a copper ground pad provided in the second surface of the substrateof the package, thermally conductive epoxy is provided over an extremityof the stand-off of the heat spreader and the exposed surface of thecopper ground pad.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The prior art heat spreader interconnect methodology forthermally enhanced PBGA package is shown in cross section in FIG. 1 asan example of a die-up mounting method. For applications where thedie-up method of mounting the device does not meet thermal requirements,the die-down method is frequently used whereby substrates are used thathave been provided with metal heat-distribution surfaces (heat slugs). Adie-down BGA package typically has better thermal performance than thedie-up PBGA package since the heat that is generated in the die can bedissipated effectively from the backside of the die to the metal heatslugs. However, the assembly cost for this die-down arrangement isconsiderably higher than for the die-up method of mounting semiconductordevices.

[0024] Shown in the cross section of FIG. 1 are the following elementsof a die-up thermally enhanced PBGA package:

[0025]10, the semiconductor die of the thermally enhanced PBGA package,mounted over the surface of substrate 12

[0026]12, a substrate or semiconductor die mounting support; it must beunderstood that conventionally substrate 12 is used for the creation ofmultiple, complex and overlying layers of interconnect traces; theseinterconnect traces have not been highlighted in the cross section ofFIG. 1 and essentially connect contact points or contact pads that areprovided over a first surface of substrate 12 with contact points orcontact pads that are provided over a second surface of substrate 12;examples of contact pads over a first surface of substrate 12 have beenprovided with contact pads highlighted as 22, examples of contact padsover a second surface of substrate 12 have been provided with contactpads highlighted as 24 and 26

[0027]14, the heat sink of the package

[0028]16, a first solder mask layer, typically comprising a patternedand etched layer of dielectric, with openings that align with thecontact pads 22; first solder mask 16 is created over a first surface ofsubstrate 12

[0029]18, a second solder mask layer, typically comprising a patternedand etched layer of dielectric, with openings that align with the coppertraces 24; second solder mask 18 is created over a second surface ofsubstrate 12

[0030]20, interconnect vias provided through substrate 12, creatingelectrical interconnects between contact pad on a first surface ofsubstrate 12 and contact pad on a second surface of substrate

[0031]22, conductive traces or contact pads on a first surface ofsubstrate 12, conductive traces 22 are connected to traces 26 by meansof vias 20 or by means of other interconnect traces (not shown) that arepart of the substrate 12

[0032]24, ground pads provided over a second surface of substrate 12,these ground pads 24 are the physical interfaces between the heatspreader 14 and the substrate 12

[0033]26, contact points provided over the second surface of substrate12

[0034]28, solder balls for further interconnect (not shown) of thepackage that is shown in cross section in FIG. 1 with surroundingelectrical circuitry or electrical components (not shown); of the solderballs that are shown in the cross section of FIG. 1, it must be notedthat some of these solder balls, such as solder ball 28, do notpenetrate through the layer 16 and therefore do not make directelectrical contact with points of electrical contact provided in or onthe first surface of substrate 12; other solder balls, such as solderball 28′ completely penetrate through the solder mask 16 and thereforemake contact with conductive traces (not shown) over the surface of thesubstrate 12; other solder balls again, such as solder balls 23″,partially penetrate through the solder mask 16 and make contact withcontact pads 22 provided over a first surface of substrate 12

[0035]30, a layer of thermally conductive adhesive interfacing betweendie 10 and the second surface of substrate 12

[0036]32, points of electrical contact provided over the active surfaceof semiconductor die 10

[0037]34, bond wires for the interconnection of die 10 to contact pads26 provided over a second surface of substrate 12

[0038]36, a mold compound formed over the surface of the structure,which further also surrounds bond wires 34.

[0039] Conventional methods that are applied for the improvement ofthermally enhanced PBGA packages concentrate on:

[0040] increasing the density of the copper that is used in the creationof the substrate of the package

[0041] including an increasing number of metal layers in the substrateof the package

[0042] applying methods of enhanced integration of the heat spreader ofthe package into the package, typically using an adhesive for thispurpose

[0043] increasing the thickness of the metal layers in the substrate ofthe package, and

[0044] adding more thermally conductive parts, vias and solder balls tothe substrate of the package, specifically to surface areas of thesubstrate that align with the thereover mounted semiconductor die of thepackage.

[0045] Specifically highlighted in the cross section of FIG. 1 are theheat spreader standoff features 38 of the heat spreader, which form thesurfaces and method of interfacing the heat spreader 14 with thesubstrate 12 of the PBGA package. Heat spreader 14 may comprise metal ofmay comprise thermally conductive epoxy.

[0046] The interconnect methodology of the invention will now bedescribed in detail using the cross sections of FIGS. 2 through 5b. Thisdescription will specifically concentrate on the methods in which theheat sink of a thermally enhanced PBGA package interfaces with and isaligned with the substrate of the package, an interface that forconventional PBGA packages has been highlighted as the stand-off 38 ofFIG. 1.

[0047] Specifically referring now to the cross sections of FIGS. 2a and2 b, there is shown a first interconnect methodology of a thermallyenhanced PBGA package 40. The physical interface 42 between the heatsink 14 and the substrate 12 is referred to as the standoff 42 of theheat spreader 14. The standoff 42 has been shown in magnified form inorder to highlight the following details of interconnect 42:

[0048]44, a copper pad that is provided over a second surface ofsubstrate 12, which at least partially penetrates through the soldermask 18 in order to establish firm mechanical interface between the heatsink 14 and substrate 12

[0049]46, conductive epoxy provided overlying copper pad 44

[0050]51, a horizontal section of the heat spreader 14

[0051]53, an upper section of the stand-off section 42 of the heatspreader 14

[0052]55, a center section of the stand-off section 42 of the heatspreader 14

[0053]57, a lower section of the stand-off section 42 of the heatspreader 14, the lower section 57 of the heat spreader stand-off 42comprises, progressing in a direction away from the horizontal section51 of the heat spreader 14:

[0054]59, a first horizontal section being parallel with the surface ofthe substrate 12, followed by

[0055]61, a U-shaped extrusion with a lower side of the U-shapedextrusion facing the substrate and with the two remaining sides of theU-shaped extrusion interfacing with the surface of the substrate underan angle, followed by

[0056]63, a second horizontal section being connected to the U-shapedextrusion, the second horizontal section being parallel with the surfaceof the substrate 12, and

[0057]65, an opening that has been created through the bottom layer ofthe U-shaped extrusion 61, overlying the copper pad 44.

[0058] Additional elements that are shown in the cross sections of FIGS.2a and 2 b but that have not been highlighted will be recognized asbeing identical to the corresponding elements that have previously beenhighlighted in the cross section of FIG. 1. Because of this partialidentity between the cross sections of FIGS. 2a and 2 b and FIG. 1,these elements will for reasons of avoidance of repetition and forreasons of simplicity of presentation not be repeated at this time.These elements are included in the description of the cross section ofFIGS. 2a and 2 b by reference to the cross section of FIG. 1.

[0059] Not highlighted in the cross sections of FIGS. 2a and 2 b are thelayers of mold compound that are applied to mount the semiconductor dieover the surface of the substrate and to thereby further complete thepackage of the semiconductor die. These layers of mold compound havebeen highlighted as layer 36 in the cross section of FIG. 1, the layerof mold compound 36 that underlies the heat sink 14 is a first (applied)layer of mold compound, the layer of mold compound that overlies theheat sink 14 is a second (applied) layer of mold compound. For thecompletion of the thermally enhanced PBGA package of the invention,these layers of mold compound are assumed to also be

[0060] The applied mold compound can be cured as part of creating thethermally enhance PBGA package, as can the thermally conductive epoxythat is inserted underneath the mounted semiconductor device as anunderfill for that device.

[0061] In addition, for completion of the thermally enhance PBGApackage, end-of-line processing can be provided, comprising steps ofconnecting contact balls to the first surface of the substrate 12, whichcompletes the creation of a Plastic Ball Grid Array (PBGA) package.

[0062] The above provided comments; relating to the application oflayers of (first and second) mold compound and end-of-line processing,equally applies to the cross sections of FIGS. 3 through 5 and arehereby made part of the descriptions of these cross sections that areprovided below.

[0063] Element 12 in the cross sections of FIGS. 2a and 2 b has beenreferred to as a substrate. This term is not to be interpreted in anylimited sense but can be interpreted as being a semiconductor devicemounting support. As semiconductor device mounting support can servesurfaces consisting of semiconductor substrates, printed circuit boards,flex circuits, metallized substrates, glass substrates and semiconductordevice mounting support. The cited semiconductor substrate may beselected from the group of substrates consisting of semiconductorsubstrates, ceramic substrates, glass substrates, gallium arsenidesubstrates, silicon substrates comprising a single layer of material,such as a silicon wafer or comprising silicon on insulator (SOI)technology and silicon on sapphire (SOS) technology, doped or undopedsemiconductors, epitaxial layers of silicon supported by a basesemiconductor, sapphire substrates or substrates used for flat paneldisplays.

[0064] In the cross sections that are shown in FIGS. 2a and 2 b, thestandoff 42 of the heat spreader 14 is inserted into or aligned with acopper pad 44 provided over the surface of the substrate 12. The throughhole 65 of the heat spreader standoff 42 allows the copper or ground pad44 to function as a positioning guide for the positioning of the heatspreader 14 with respect to the substrate 12 over which the heatspreader 14 is mounted. The heat spreader 14 is connected to the groundpad 44 using a conductive epoxy 46 for heat spreading purposes, thethermally conductive epoxy 46 is applied using an epoxy dispensingprocess. A baking process cures the thermally conductive epoxy 46 inorder to assure firm holding of the heat spreader 14 prior to the stepsof encapsulation and molding (not From the cross sections that are shownin FIGS. 2a and 2 b, it is, in sum, clear that:

[0065] the heatsink 14 is aligned with the substrate 12 by means of thecopper pad 44 that is provided over the second surface of substrate 12,and

[0066] the heatsink is connected to the ground pad 44 by thermallyconductive epoxy 46.

[0067] Referring now to the cross sections that are shown in FIGS. 3aand 3 b, there is shown a second interconnect methodology of a thermallyenhanced PBGA package SQ. The physical interface between the heat sink14 and the substrate 12, also referred to as the stand-off 52 of theheat spreader 14, has been shown in magnified form in order to highlightthe following details 6 f stand-off 52 and the interfacing with thesurface 12:

[0068]54, a copper pad that is provided over a second surface ofsubstrate 12, which penetrates through the solder mask 18 in order toestablish firm mechanical interface between the heat sink 14 andsubstrate 12

[0069]56, a gold stud bump, created overlying and in contact with copperpad 54, and

[0070]58, conductive epoxy that has been inserted overlying a gold studbump 56 and copper pad 54.

[0071] Additional elements that are shown in the cross sections of FIGS.3a and 3 b but that have not been individually highlighted in the crosssections of FIGS. 3a and 3 b will be recognized as being identical tothe corresponding elements that have previously been highlighted in thecross section of FIG. 1. Because of this partial identity between thecross sections of FIGS. 3a and 3 b and FIG. 1, these elements will forreasons of avoidance of repetition and for reasons of simplicity ofpresentation not be repeated at this time. These elements are includedin the description of the cross sections of FIGS. 3a and 3 b byreference to the cross section of FIG. 1.

[0072] The cross section of the stand-off 52 of the heat spreader 14 asshown in FIGS. 3a and 3 b will be recognized as being identical to thecross section of the stand-off 42 of the heat spreader 14 that has beendiscussed in detail in the cross sections of FIGS. 2a and 2 b. Becauseof this identity, this detailed description will not be repeated at thistime but will be included by reference in the description of the crosssections of FIGS. 3a and 3 b.

[0073] In the cross sections that are shown in FIGS. 3a and 3 b, thestandoff of the heat spreader has a through hole, the heat spreader 14is inserted or aligned with the underlying substrate 12 using a goldstud bump 56. The stud bump 56 will be formed applying single ormultiple steps of creating overlying layers of bump material. The heatspreader 14 is connected to the ground pad 54 using the conductive epoxy58 by a dispensing process. Curing of the conductive epoxy 53 is appliedby a baking process, thus providing a firm positioning of the heatspreader 14 prior to encapsulation and molding.

[0074] From the cross sections that are shown in FIGS. 3a and 3 b, itis, in sum, clear that:

[0075] the heatsink 14 is aligned with the substrate 12 by means of thegold stud bump 56 that is provided over the second surface of substrate12

[0076] the heatsink 14 is thermally connected to the ground pad 54 bythermally conductive epoxy 58.

[0077] Referring to the cross sections that are shown in FIGS. 4a and 4b, there is shown a third interconnect methodology of a thermallyenhanced PBGA package 60. The physical interface 62 between the heatsink 14 and the substrate 12 has been shown in magnified form in orderto highlight the following details of interconnect 62:

[0078]64, a copper pad that is provided over a second surface ofsubstrate 12, which penetrates through the solder mask 18 in order toestablish firm mechanical interface between the heat sink 14 andsubstrate 12, and

[0079]66, a solder ball, created overlying and in contact with copperpad 64.

[0080] Additional elements that are shown in and that are part of thecross sections of FIGS. 4a and 4 b but that have not been individuallyhighlighted in the cross sections of FIGS. 4a and 4 b Will be recognizedas being identical to the corresponding elements that have previouslybeen highlighted in the cross section of FIG. 1. Because of this partialidentity between the cross sections of FIGS. 4a and 4 b and FIG. 1,these elements will for reasons of avoidance of repetition and forreasons of simplicity of presentation not be repeated at this time.These elements are included in the description of the cross sections ofFIGS. 4a and 4 b by reference to the cross section of FIG. 1.

[0081] In the cross sections that are shown in FIGS. 4a and 4 b, thestand off 62 of the heat spreader 14 is inserted or aligned in thepre-attached solder ball 64 or by the use of solder paste (not shown).The flux-free solder ball 66 or solder paste is attached after wirebonding. The copper ground pad 64 is connected to the heat spreader 14by soldering or by reflow.

[0082] The cross section of the stand-off 62 of the heat spreader 14 asshown in FIGS. 4a and 4 b will be recognized as being identical to thecross section of the stand-off 42 of the heat spreader 14 that has beendiscussed in detail in the cross sections of FIGS. 2a and 2 b. Becauseof this identity, this detailed description will not be repeated at thistime but will be included by reference in the description of the crosssections of FIGS. 4a and 4 b.

[0083] From the cross sections that are shown in FIGS. 4a and 4 b, itis, in sum, clear that the heatsink 14 is aligned with the substrate 12by means of the solder ball 66 that is provided over the second surfaceof substrate 12. The heatsink 14 will be connected to the substrate 12by soldering or by a process of solder reflow.

[0084] Referring to the cross sections that are shown in FIGS. 5a and 5b, there is shown a fourth interconnect methodology of a thermallyenhanced PBGA package 70. The physical interface 72, referred to as thestand-off of the heat spreader 14, between the heat sink 14 and thesubstrate 12 has been shown in magnified form in order to highlight thefollowing details of interconnect 52:

[0085]74, a copper pad that is provided over a second surface ofsubstrate 12, which penetrates through the solder mask 18 in order toestablish firm mechanical interface between the heat sink 14 andsubstrate 12, and

[0086]76, conductive epoxy that has been provided overlying the copperpad 74.

[0087] The separate elements of the standoff 72 of the heat spreadershown in cross sections in FIGS. 5a and 5 b are the

[0088]71, a horizontal section of the heat spreader 14

[0089]73, an upper section of the stand-off section 42 of the heatspreader 14

[0090]75, a center section of the stand-off section 42 of the heatspreader 14

[0091]77, a lower section of the stand-off section 72 of the heatspreader 14, the lower section 77 of the heat spreader stand-off 72comprises, progressing in a direction away from the horizontal section71 of the heat spreader 14:

[0092]79, a first horizontal section being parallel with the surface ofthe substrate 12, followed by

[0093]81, a center section, interfacing with the surface of thesubstrate 12 under an angle, followed by

[0094]83, a second horizontal section being connected to the centersection 81, the second horizontal section 83 being parallel with thesurface of the substrate 12; further shown in the cross sections ofFIGS. 5a and 5 a is element 78, which is a heat spreader stand-off ballor stud that is physically connected to or part of the heat spreader 14and that provides additional stability to the interconnect between theheat spreader 14 and the substrate 12.

[0095] Additional elements that are shown in and that are part of thecross sections of FIGS. 5a and 5 b but that have not been individuallyhighlighted in the cross sections of FIGS. 5a and 5 b Will be recognizedas being identical with the corresponding elements that have previouslybeen highlighted in the cross section of FIG. 1. Because of this partialidentity between the cross sections of FIGS. 5a and 5 b and FIG. 1,these elements will for reasons of avoidance of repetition and forreasons of simplicity of presentation not be repeated at this time.These elements are included in the description of the cross sections ofFIGS. 5a and 5 b by reference to the cross section of FIG. 1.

[0096] In the cross sections that are shown in FIGS. 5a and 5 b, thepedestal or foot 83 of the heat spreader is positioned on the ground pad74 provided over the surface of the substrate 12. For improvedconductivity, a thermally conductive epoxy 76 is dispensed over the foot83 and ground pad 74, followed by a curing process to firmly hold theheat spreader 14 in place. A heat spreader stand-off ball or stud 78 ispart of the heat spreader 14 in order to maintain improved planarity ofthe heat spreader 14 with respect to the surface of the substrate 12.

[0097] From the cross sections that are shown in FIGS. 5a and 5 b, itis, in sum, clear that the heatsink 14 is thermally connected to theground pad 74 by thermally conductive epoxy 76.

[0098] In addition, the heat spreader 14 is provided with a heatspreader standoff ball or stud 78, which provides for firm mechanicalinterfacing between the heat spreader 14 and the second surface ofsubstrate 12.

[0099] Although the invention has been described and illustrated withreference to specific illustrative embodiments thereof, it is notintended that the invention be limited to those illustrativeembodiments. Those skilled in the art will recognize that variations andmodifications can be made without departing from the spirit of theinvention. It is therefore intended to include within the invention allsuch variations and modifications which fall within the scope of theappended claims and equivalents thereof.

What is claimed is:
 1. A thermally enhanced Plastic Ball Grid Array(PBGA) package comprising a heat sink for mounting over a surface of asubstrate of the thermally enhanced Plastic Ball Grid Array (PBGA)package, said heat sink comprising: (a) a horizontal section beingparallel with a substrate over which said heat spreader is beingmounted, said horizontal section having a perimeter; (b) heat spreaderstand-off sections extending from said perimeter of said horizontalsection, a lower section of said heat spreader stand-off sectionsforming a physical interface between said heat spreader and saidsubstrate over which said heat spreader is being mounted; (c) each ofsaid heat spreader standoff sections comprising: (i) an upper sectionbeing connected with said horizontal section of said heat spreader underan angle (ii) a center section being connected with said upper sectionin a plane of said upper section, and (iii) said lower section beingconnected with said center section of said heat spreader standoffsection; (d) each lower section of each of said heat spreader standoffsections comprising: (i) a first horizontal section being parallel withthe surface of said substrate, said first horizontal section beingconnected with said lower section of said heat spreader stand-offsection; (ii) a U-shaped extrusion connected with said first horizontalsection, with a lower side of said U-shaped extrusion facing saidsubstrate, with two retaining sides of said U-shaped extrusioninterfacing with the surface of said substrate under an angle, with atleast one opening having been created through said lower side of saidU-shaped extrusion; and (iii) a second horizontal section connected tosaid U-shaped extrusion.
 2. The thermally enhanced Plastic Ball GridArray (PBGA) package of claim 1, additionally comprising: a substratehaving a first and a second surface, at least one metal pad having beenprovided over the second surface of said substrate, additionally atleast one semiconductor device having been mounted and interconnectedover said second surface of said substrate; said heat spreader havingbeen positioned over said second surface of said substrate; said atleast one metal pad having been aligned with said at least one openingcreated through said lower side of said U-shaped extrusion; said atleast one metal pad having been inserted into said at least one openingcreated through said lower side of said U-shaped extrusion; and at leastone supply of thermally conductive epoxy having been provided over thesurface of said at least one metal pad, thereby at least overlying saidlower side of said U-shaped extrusion with a layer of said thermallyconductive epoxy.
 3. The method of claim 2, said at least one metal padcomprising copper.
 4. The thermally enhanced Plastic Ball Grid Array(PBGA) package of claim 1, additionally comprising: a substrate having afirst and a second surface, at least one metal pad having been providedover the second surface of said substrate, said at least one metal padhaving been provided with a stud bump over the surface thereof,additionally at least one semiconductor device having been mounted andinterconnected over said second surface of said substrate; said heatspreader having been positioned over said second surface of saidsubstrate; said stud bump provided over the surface of said at least onemetal pad having been aligned with said at least one opening createdthrough said lower side of said U-shaped extrusion; said at least onestud bump having been inserted into said at least one opening createdthrough said lower side of said U-shaped extrusion; and at least onesupply of thermally conductive epoxy or solder paste having beenprovided over the surface of said stud bump provided over said at leastone metal pad, thereby overlying said stud bump and further at leastoverlying said lower side of said U-shaped extrusion with a layer ofsaid thermally conductive epoxy or solder paste.
 5. The structure ofclaim 4, said at least one metal pad comprising copper.
 6. The structureof claim 4, said stud bump comprising gold.
 7. The thermally enhancedPlastic Ball Grid Array (PBGA) package of claim 1, additionallycomprising: a substrate having a first and a second surface, at leastone metal pad having been provided over the second surface of saidsubstrate, said at least one metal pad having been provided with asolder ball over the surface thereof, additionally at least onesemiconductor device having been mounted and interconnected over saidsecond surface of said substrate; said heat spreader positioned oversaid second surface of said substrate; said solder bump provided oversaid at least one metal pad having been aligned with said at least oneopening created through said lower side of said U-shaped extrusion; andsaid solder bump having been inserted into said at least one openingcreated through said lower side of said U-shaped extrusion.
 8. Thestructure of claim 7, said metal pad comprising copper.
 9. A thermallyenhanced Plastic Ball Grid Array (PBGA) package comprising a heat sinkfor mounting over a surface of a substrate of the thermally enhancedPlastic Ball Grid Array (PBGA) package, said heat sink comprising: (a) ahorizontal section being parallel with a substrate over which said heatspreader is being mounted, said horizontal section having extremitiesaround a perimeter thereof; (b) heat spreader stand-off sectionsextending from said perimeter of said horizontal section, a secondhorizontal section of a lower section of said heat spreader stand-offsections forming a physical interface between said heat spreader andsaid substrate; (c) each of said heat spreader standoff sectionscomprising: (i) an upper section being connected to said horizontalsection of said heat spreader under an angle; (ii) a first centersection being connected with said upper section of said heat spreaderstandoff section in a plane of said upper section; (iii) a lower sectionbeing connected with said first center section of said heat spreaderstand-off section, said lower section comprising: (1) a first horizontalsection connected with said lower section of said heat spreaderstand-off section, said first horizontal section being parallel with thesurface of said (2) a second center section intersecting connected withsaid first horizontal section, said second center section intersectingthe surface of said substrate under an angle; (3) said second horizontalsection connected to said second center section; and (4) an essentiallyspherically shaped supportive metal interface between said firsthorizontal section of said lower section of said heat spreader stand-offsection and the surface of said substrate as a physical extension ofsaid first horizontal section.
 10. The thermally enhanced Plastic BallGrid Array (PBGA) package of claim 4, additionally comprising: asubstrate having a first and a second surface, at least one metal padhaving been provided over the second surface of said substrate,additionally at least one semiconductor device having been mounted andinterconnected over said second surface of said substrate; said heatspreader positioned over said second surface of said substrate; said atleast one metal pad having been aligned with said second horizontalsection of said lower section thereby positioning said second horizontalsection of said lower section over said at least one metal pad by afirst measurable amount, exposing the surface of said at least one metalpad by a second measurable amount; and providing at least one supply ofthermally conductive epoxy over the surface of said second horizontalsection of said lower section, thereby including the exposed surface ofsaid at least one metal pad provided in a second surface of saidsubstrate.
 11. The structure of claim 10, said at least one metal padcomprising copper.
 12. A method for packaging a semiconductor device,forming a Plastic Ball Grid Array (PBGA) package, comprising the stepsof: (A) providing a semiconductor device mounting support having a firstand a second surface, said semiconductor device mounting support havingbeen provided with interconnect traces and at least one metal padtherein or thereover; (B) mounting at least one semiconductor deviceover the second surface of said semiconductor device mounting support;(C) connecting said at least one semiconductor device in a face upwardposition by facing an active surface of said at least one semiconductordevice away from said semiconductor device mounting support, usinginterconnect wires between said interconnect traces provided in saidsemiconductor device mounting support and contact points provided in anactive surface of said at least one semiconductor device; (D)positioning a heat spreader over the surface of said substrate, saidheat spreader comprising: (a) a horizontal section being parallel with asemiconductor device mounting support over which said heat spreader isbeing mounted, said horizontal section having a (b) heat spreaderstandoff sections extending from said perimeter of said horizontalsection, a lower section of said heat spreader stand-off sectionsforming a physical interface between said heat spreader and saidsemiconductor device mounting support over which said heat spreader isbeing mounted; (c) each of said heat spreader standoff sectionscomprising: (i) an upper section being connected to said horizontalsection of said heat spreader under an angle (ii) a center section beingconnected with said upper section in a plane of said upper section, and(iii) said lower section being connected with said center section ofsaid heat spreader standoff section; (d) each lower section of each ofsaid heat spreader standoff sections comprising: (i) a first horizontalsection being parallel with the surface of said semiconductor devicemounting support, said first horizontal section being connected withsaid lower section of said heat spreader stand-off section; (ii) aU-shaped extrusion connected with said first horizontal section, with alower side of said U-shaped extrusion facing said semiconductor devicemounting support, with two remaining sides of said U-shaped extrusioninterfacing with the surface of said semiconductor device mountingsupport under an angle, with at least one opening having been createdthrough said lower side of said U-shaped extrusion; and (iii) a secondhorizontal section connected to said U-shaped extrusion; and (E) havingmounted and interconnected at least one semiconductor device, furthercreating a mold compound overlying at least part of said heat spreader.13. The method of claim 12, additionally curing said mold compound andsaid thermally conductive epoxy.
 14. The method of claim 12, said heatspreader comprising metal.
 15. The method of claim 12, said heatspreader comprising thermally conductive epoxy.
 16. The method of claim12, in addition providing end-of-line processing for said packaging ofsaid semiconductor device, said end-of-line processing comprising stepsof connecting contact balls to the first surface of said semiconductordevice mounting support, completing creation of a thermally enhancedPlastic Ball Grid Array (PBGA) package.
 17. The method of claim 12,additionally comprising the steps of: aligning said at least one metalpad with said at least one opening created through said lower side ofsaid U-shaped extrusion; inserting said at least one metal pad havinginto said at least one opening created through said lower side of saidU-shaped extrusion; and supplying thermally conductive epoxy over thesurface of said at least one metal pad, thereby at least overlying saidlower side of said U-shaped extrusion with a layer of said thermallyconductive epoxy.
 18. The method of claim 12, said at least one metalpad comprising copper.
 19. The method of claim 12, said at least onemetal pad serving as ground pad.
 20. A method for packaging asemiconductor device, forming a Plastic Ball Grid Array (PBGA) package,comprising the steps of: (A) providing a semiconductor device mountingsupport having a first and a second surface, said semiconductor devicemounting support having been provided with interconnect traces and atleast one metal pad therein or thereover, a stud bump having beenprovided over the surface of said at least one metal pad; (B) mountingat least one semiconductor device over the second surface of saidsemiconductor device mounting support; (C) connecting said at least onesemiconductor device in a face upward position by facing an activesurface of said at least one semiconductor device away from saidsemiconductor device mounting support, using interconnect wires betweensaid interconnect traces provided in said semiconductor device mountingsupport and contact points provided in an active surface of said atleast one semiconductor device; (D) positioning a heat spreader over thesurface of said semiconductor mounting support, said heat spreadercomprising: (a) a horizontal section being parallel with a semiconductordevice mounting support over which said heat spreader is being mounted,said horizontal section having a (b) heat spreader stand-off sectionsextending from said perimeter of said horizontal section, a lowersection of said heat spreader stand-off sections forming a physicalinterface between said heat spreader and said semiconductor devicemounting support over which said heat spreader is being mounted; (c)each of said heat spreader standoff sections comprising: (i) an uppersection being connected to said horizontal section of said heat spreaderunder an angle (ii) a center section being connected with said uppersection in a plane of said upper section, and (iii) said lower sectionbeing connected with said center section of said heat spreader standoffsection; (d) each lower section of each of said heat spreader standoffsections comprising: (i) a first horizontal section being parallel withthe surface of said semiconductor device mounting support, said firsthorizontal section being connected with said lower section of said heatspreader stand-off section; (ii) a U-shaped extrusion connected withsaid first horizontal section, with a lower side of said U-shapedextrusion facing said semiconductor device mounting support, with tworemaining sides of said U-shaped extrusion interfacing with the surfaceof said semiconductor device mounting support under an angle, with atleast one opening having been created through said lower side of saidU-shaped extrusion; and (iii) a second horizontal section connected tosaid U-shaped extrusion; and (E) mounting and interconnecting at leastone semiconductor device, further creating mold compound overlying atleast part of said heat spreader.
 21. The method of claim 20,additionally curing said mold compound and said thermally conductiveepoxy.
 22. The method of claim 20, said heat spreader comprising metal.23. The method of claim 20, said heat spreader comprising thermallyconductive epoxy.
 24. The method of claim 20, in addition providingend-of-line processing for said packaging of said semiconductor device,said end-of-line processing comprising steps of connecting contact ballsto the first surface of said semiconductor device mounting support,completing creation of a thermally enhanced Plastic Ball Grid Array(PBGA) package.
 25. The method of claim 20, additionally comprising thesteps of: aligning said stud bump provided over the surface of said atleast one metal pad with said at least one opening created through saidlower side of said U-shaped extrusion; inserting said at least one studbump into said at least one opening created through said lower side ofsaid U-shaped extrusion; and supplying thermally conductive epoxy orsolder paste over the surface of said at least one metal pad, thereby atleast overlying said stud bump and further at least overlying said lowerside of said U-shaped extrusion with a layer of said thermallyconductive epoxy or solder paste.
 26. The method of claim 20, said atleast one metal pad comprising copper.
 27. The method of claim 20, saidat least one metal pad serving as ground pad.
 28. The method of claim20, said stud bump comprising gold.
 29. A method for packaging asemiconductor device, forming a Plastic Ball Grid Array (PBGA) package,comprising the steps of: (A) providing a semiconductor device mountingsupport having a first and a second surface, said semiconductor devicemounting support having been provided with interconnect traces and atleast one metal pad therein or thereover, a solder bump having beenprovided over the surface of said at least one metal (B) mounting atleast one semiconductor device over the second surface of saidsemiconductor device mounting support; (C) connecting said at least onesemiconductor device in a face upward position by facing an activesurface of said at least one semiconductor device away from saidsemiconductor device mounting support, using interconnect wires betweensaid interconnect traces provided in said semiconductor device mountingsupport and contact points provided in an active surface of said atleast one semiconductor device; (D) positioning a heat spreader over thesurface of said semiconductor mounting support, said heat spreadercomprising: (a) a horizontal section being parallel with a semiconductordevice mounting support over which said heat spreader is being mounted,said horizontal section having a perimeter; (b) heat spreader stand-offsections extending from said perimeter of said horizontal section, alower section of said heat spreader stand-off sections forming aphysical interface between said heat spreader and said semiconductordevice mounting support over which said heat spreader is being mounted;(c) each of said heat spreader standoff sections comprising: (i) anupper section being connected to said horizontal section of said heatspreader under an angle (ii) a center section being connected with saidupper section in a plane of said upper section, and (iii) said lowersection being connected with said center section of said heat spreaderstandoff section; (d) each lower section of each of said heat spreaderstandoff sections comprising: (i) a first horizontal section beingparallel with the surface of said semiconductor device mounting support,said first horizontal section being connected with said lower section ofsaid heat spreader stand-off section; (ii) a U-shaped extrusionconnected with said first horizontal section, with a lower side of saidU-shaped extrusion facing said semiconductor device mounting support,with two remaining sides of said U-shaped extrusion interfacing with thesurface of said semiconductor device mounting support under an angle,with at least one opening having been created through said lower side ofsaid U-shaped extrusion; and (iii) a second horizontal section connectedto said U-shaped extrusion; and (E) mounting and interconnecting atleast one semiconductor device, further creating mold compound overlyingat least part of said heat spreader.
 30. The method of claim 29,additionally curing said mold compound and said thermally conductiveepoxy.
 31. The method of claim 29, said heat spreader comprising metal.32. The method of claim 29, said heat spreader comprising thermallyconductive epoxy.
 33. The method of claim 29, in addition providingend-of-line processing for said packaging of said semiconductor device,said end-of-line processing comprising steps of connecting contact ballsto the first surface of said semiconductor device mounting support,completing creation of a thermally enhanced Plastic Ball Grid Array(PBGA) package.
 34. The method of claim 29, additionally comprising thesteps of: aligning said solder bump provided over the surface of said atleast one metal pad with said at least one opening created through saidlower side of said U-shaped extrusion; and inserting said at least onesolder bump into said at least one opening created through said lowerside of said U-shaped extrusion.
 35. The method of claim 29, said atleast one metal pad comprising copper.
 36. The method of claim 29, saidat least one metal pad serving as ground pad.
 37. A method for packaginga semiconductor device, forming a Plastic Ball Grid Array (PBGA)package, comprising the steps of: (A) providing a semiconductor devicemounting support having a first and a second surface, said semiconductordevice mounting support having been provided with interconnect tracesand at least one metal pad therein or thereover, a solder bump havingbeen provided over the surface of said at least one metal pad; (B)mounting at least one semiconductor device over the second surface ofsaid semiconductor device mounting support; (C) connecting said at leastone semiconductor device in a face upward position by facing an activesurface of said at least one semiconductor device away from saidsemiconductor device mounting support, using interconnect wires betweensaid interconnect traces provided in said semiconductor device mountingsupport and contact points provided in an active surface of said atleast one semiconductor device; (D) positioning a heat spreader over thesurface of said semiconductor device mounting support, said heatspreader comprising: (a) a horizontal section being parallel with asemiconductor device mounting support over which said heat spreader isbeing mounted, said horizontal section having extremities around aperimeter thereof; (b) heat spreader stand-off sections extending fromsaid perimeter of said horizontal section, a second horizontal sectionof a lower section of said heat spreader stand-off sections forming aphysical interface between said heat spreader and said semiconductordevice mounting support; (c) each of said heat spreader standoffsections comprising: (i) an upper section being connected to saidhorizontal section of said heat spreader under an angle; (ii) a firstcenter section being connected with said upper section of said heatspreader standoff section in a plane of said upper section; (iii) alower section being connected with said first center section of saidheat spreader stand-off section, said lower section comprising: (1) afirst horizontal section connected with said lower section, said firsthorizontal section being parallel with the surface of said semiconductordevice mounting support; (2) a second center section intersectingconnected with said first horizontal section, said second center sectionintersecting the surface of said semiconductor device mounting supportunder an angle; (3) said second horizontal section connected to saidsecond center section; and (4) an essentially spherically shapedsupportive metal interface between said first horizontal section of saidlower section of said heat spreader stand-off section and the surface ofsaid semiconductor device mounting support as a physical extension ofsaid first horizontal section; and (E) mounting and interconnecting atleast one semiconductor device, further creating mold compound overlyingat least part of said heat spreader.
 38. The method of claim 37,additionally curing said mold compound and said thermally conductiveepoxy.
 39. The method of claim 37, said heat spreader comprising metal.40. The method of claim 37, said heat spreader comprising thermallyconductive epoxy.
 41. The method of claim 37, in addition providingend-of-line processing for said packaging of said semiconductor device,said end-of-line processing comprising steps of connecting contact ballsto the first surface of said semiconductor device mounting support,completing creation of a thermally enhanced Plastic Ball Grid Array(PBGA) package.
 42. The method of claim 37, additionally comprising thesteps aligning said at least one metal pad with said second horizontalsection of said lower section thereby positioning said second horizontalsection of said lower section over said at least one metal pad by afirst measurable amount, exposing the surface of said at least one metalpad by a second measurable amount; and providing at least one supply ofthermally conductive epoxy over the surface of said second horizontalsection of said lower section, thereby including the exposed surface ofsaid at least one metal pad provided in a second surface of saidsemiconductor device mounting support.
 43. The method of claim 37, saidat least one metal pad comprising copper.
 44. The method of claim 37,said at least one metal pad serving as ground pad.
 45. The structure ofclaim 4, said stud bump comprising copper.
 46. The method of claim 20,said heat spreader comprising solder
 47. The method of claim 20, saidstud bump comprising copper.
 48. The method of claim 29, said heatspreader comprising solder